In June 2012, I tried to order a camera accessory for my sister’s birthday. She lives over 1000 miles away in Florida. Newegg declined the $50 order, even though I’d selected my usual billing address and credit card (on file with them!). I tried another card. Also declined. I checked with my card provider, USBank, and they reported no problems.

At this point, I called Newegg’s credit department, expecting an explanation and resolution. I said, “My billing address and credit card information is perfect. USBank says there’s no issue. Are you declining the order because I’m shipping a gift to a family member?” The customer service agent couldn’t comment on their fraud detection policies. I gave up and ordered the gift through Amazon: same credit card, no problems.

Sitting in my living room a few days later, I tried to login to Newegg from my wife’s laptop. I simply needed to lookup an old order. I was staring at our projector, and typing on an unfamiliar keyboard didn’t help my typing accuracy. Two wrong password attempts made me second guess myself. Then a third wrong attempt: Account locked!

I called Newegg expecting to quickly regain access to my 10+ year old account. The service agent said she’d have their fraud department look into the ban, and based on their decision, it would be usable again in 1-2 days. Newegg never followed up or restored the account even after I proposed, “So, you’re telling me to shop at Amazon?”

Fast forward to last night: I’d still been using our [separate] company account with Newegg to buy toner and office computer equipment, and decided it’s time to replace my five year old dinosaur of a PC…

Two minutes after placing a $1287.50 order, Newegg sends an email to the company, “Payment Authorization Failed”:

Again?! This is the same USBank Visa we’ve used to place Newegg orders all year! The company has a high spending limit on this particular card and we regularly charge large material and equipment purchases to the same card. All billing, shipping, and card information I’d provided was 100% correct, accurate, and legitimate.

So I call USBank again. The rep says, “Oh, Newegg? They’re one of the biggest sources of fraud we deal with. We automatically decline large orders.” He went on to mention that he and his wife recently spotted a fraudulent $3500 charge from Newegg on their own USBank Visa–and they don’t even have a Newegg account.

He kindly transfers me to 2nd level support. After re-answering all security questions and explaining that we really do want to charge $1287 to our Visa, Mr. Level-Two says, “Okay, can you try to re-submit the order at Newegg? It should go through this time.” Newegg instantly declined the card a second time.

He says, “Hm, I’m going to transfer you to the next level support. They’ll be able to help.”

At level three, I answer security questions for the third time, then ask Darleen if she really has the magical powers necessary to authorize my legitmate company purchase. She says she does. I re-enter my card at Newegg and the order finally goes through.

Online Credit Card Processing is Broken

I completely understand the importance of preventing fraudulent activity, and avoiding chargebacks. Fraud scares consumers, and businesses ultimately lose money dealing with chargebacks.

My company has processed a few thousand credit card orders in the past quarter, with 0 chargebacks. We cater to a niche market, so fraud isn’t common through our online store. Yet, we observe 5+ declined credit cards each day. The majority of these customers have made a small typo, or can’t remember if they’ve updated their billing address after moving to a new home/apartment. In all but a few rare cases, our customers’ declined cards are false positives!

Trading Buying Freedom for Security

Searches for declined credit cards turn up similar stores like my own:

• Smart Money – Credit Card Security: Too Much of a Good Thing?
• Reuters – When Your Credit Card Charge is Denied

To stop fraud, we need to stop allowing purchases to be made solely with the information that appears on the card because this is not secret information; it is basic information about an account. This is not something that merchants can fix alone. Merchants already have to foot the bill for chargebacks, and PCI standards are really just an attempt to make merchants responsible for maintaining the security of what is, at its core, a payment system that broke in the 1990s. CVN didn’t work–10 years later, we still have to explain to consumers where the number is because the card associations have not spent enough effort educating the public and, quite frankly, they don’t care. To use a credit card, anywhere, you should have to swipe it (PCI is still relevant in this scenario). Period.

Fixing Online Purchasing Security

What Happens When You Charge a Customer’s Card — via FeeFighters

Credit Card Authorization via SMS

“Do you authorize purchase of $## from Store-Name-Here? Respond ‘Y’ to authorize charge to your credit card, ending digits ####.”

My RepRap Prusa: Three months' progress

Earlier this summer my company spent a fair chunk of change on rapid prototypes printed by professional fused deposition modelling (FDM) printers. Thinking this was a huge waste of cash, Google led me to the RepRap project: Personal 3D printing for as little as $350. Of course, I had to build one.

The RepRap Wiki suggested a Prusa Mendel. Its bill of materials and instructions seemed well prepared, and the list of suppliers even seemed strong (note the keyword here–”seemed”). As an open source project, I should’ve known what I was getting into!

RepRap is a vibrant, rapidly growing opensource community for two reasons. First, people are inherently fascinated by a machine that makes real, physical objects. Second, home 3D printing is still in its infancy. Assembly of a 3D printer demands enormous exchange of ideas. One must gather a basic knowledge of electronics, programming, and machining. You’ll inevitably have questions, and once you step into the forums or IRC, it’s unlikely to be your last visit.

Consequently, RepRap is the child of thousands of ‘makers’, engineers, and programmers around the world. PhD’s and kids alike contribute to its development. The movement has resulted in a number of start-ups, including the recent $10MM VC-funded Makerbot in New York, which has subsequently brought significant media coverage to opensource 3D printing (CNN, Colbert Report, NPR, the New York Times, just to name a few). I’m impressed with the brand name they’ve established, but ultimately they’re selling an expensive kit. At 1/3 the price, and with potentially better performance, a Prusa is the way to go.

Gathering Parts

Motors and filament from Ultimachine

I thought I’d take the easy route and grab a Prusa kit off eBay. elderfarrer2hy7 had the best price at the time ($160) on a kit which included all printed parts, nuts, bolts, bearings, belts, and a laser cut acrylic bed. All I needed was a set of rods, electronics, motors and a weakly documented, but crucial piece referred to as a “hotend”. And of course some plastic filament. Or so I thought.

elderfarrer2hy7′s kit showed up within days. I then ordered:

• M8 smooth rods, Part #88625K67 at McMaster
• M8 threaded rods, Part #90024A462 at McMaster
• Kysan 1.8° NEMA 17 stepper motors at Ultimachine
• ABS filament at Ultimachine

J-Head MKIII-B Hot-End. Power resistor pictured in fuzzy right corner.

Alas, I cannot recommend the Makergear hot-end pack. First of all, it’s $75. Second, it took hours to assemble and harden. Third, it flat out failed, as I’ll explain below. Get a J-Head MKIII from “Reifsnyderb”. It’s under $65, arrives 95% assembled, and just works.

Also worth consideration is the Budaschnozzle from LulzBots for $75. I haven’t personally tried one, but it looks awesome and supposedly works equally well. Arcol.hu has a similar hotend for $134–ouch.

One of the freshly assembled Gen6 boards

For power, I went with a 12V, 15A power supply from “jingsam-online” on eBay. This is barely adequate with a heatbed connected–the supply runs at almost 70C. In retrospect, $10 more for the 30A version would have been a better investment.

Assembly – Weekend #1

6ft shipping tube of rods, and parts kit at arrival

Smooth and threaded rods arrived from McMaster in a 6ft tube. The Prusa assembly guide stated required rod lengths, but did not suggest tools for cutting the 2 meter steel rods. I’m still not sure of a preferred cutting method, but my brother-in-law brought over a dremel and we picked up some fresh rotary discs from Lowes. We spent two long evenings cutting rods. Unless you have a better idea, buy pre-cut rods.

Assembly – Weekend #2

Prusa frame assembled on kitchen table.

The majority of the frame went together the next weekend. However, we quickly hit another hurdle: PLA bushings! All of our parts were printed in ABS, including the “PLA bushings”. These pieces are supposed to enable the X, Y, and Z axis to glide freely along the smooth rods. We weren’t so lucky. Our PLA (ABS?) bushings snapped onto the smooth rods but would not budge. We filed them down and tried other suggestions from the RepRap forums to no avail.

I remembered a line from the Prusa Wiki which mentioned linear bearings. Aha. That’s what they were talking about. PLA bushings work for some people, and have the clear advantage of cheapness. But reliability is spotty. Serious CNC machines use linear bearings for axis movement. So, I ordered a set of LM8UU bearings from a Chinese eBay seller. [VXB sells LME8UU bearings in the USA at twice the price.]

The LM8UU mod also meant I needed a new X-carriage, Y-bed LM8UU mounts, and X-ends. These were easily found on Thingiverse.com:

• LM8UU X Carriage by Greg Frost
• LM8UU Y Axis Holders by DigiFab
• LM8UU X-End Motor Bracket and Idler by ahmetcemturan

I e-mailed elderfarrer2hy7 and he quickly hooked me up. Edit: Looks like he now sells kits made for linear bearings!

After I built my printer, Prusa himself released an official LM8UU X-end set. I’ve printed them but still prefer the design by ahmetcemturan.

Assembly – Weekends #3 and #4

While waiting for the Chinese LM8UU’s, we assembled the Makergear Hotend pack and Wade’s extruder. After much head scratching at Rick’s documentation, we had an assembled heatcore and Groovemount.

Cutting the hobbed bolt was a disaster. Again, we resorted to the dremel:

The best of our three hobbing attempts. Not so good.

We ended up with two failed attempts and one marginally successful “hobbed” bolt from this adventure.

For about an hour, we had no faith in the Wade’s Extruder because the filament passed through only against the hobbed bolt (no opposing force, so it kept slipping). I finally realized that we hadn’t attached the Idler block and 608 bearing…right…

I ended up ordering a hobbed bolt from Eckertech. Much, much better:

Eckertech hobbed bolt (photo taken weeks after initial hobbing attempts)

Assembly – Weekends #5 and #6

The LM8UU’s showed up after two weeks, followed closely by the finished Gen6 boards. Final assembly only took a couple days, but it was quickly apparent we were nowhere near finished.

Assembled Prusa, prior to troubleshooting

We started with the simplest problems:

• X axis, Z axis, and the extruder ran backwards. Solution: Edited FiveD firmware and calibrated X, Y, and Z steps_per_mm.
• Y axis would only travel forward. Solution: My soldering had killed the Y mechanical endstop. Replaced with a microswitch from RadioShack.

Pile of junk ABS extrusion after hours of jams

MakerGear Trouble – After knocking out the simple stuff, we tried to extrude plastic. And that’s when the real problems began. We spent about six hours with the Makergear hotend, yet only managed to produce a small pile of extruded ABS. This took days to troubleshoot. Here’s what I learned:

1. We first tried to extrude ABS at 245C. When this failed (actually due to bad hobbing), we switched to PLA at 240C. Dumb move. The PLA expanded, jammed, and slowly burned up in the Makergear hotend. We had to drill it out. So, never set temps too high. PLA should be used at 180-220C. ABS: 220-250C.
2. We had enormous difficulty with the springs elderfarrer2hy7 provided. They lacked sufficient force, so the hobbed bolt would spin without pushing plastic and thus slowly strip the filament. The filament could be manually extruded by hand, if not already jammed. In short, Wade’s Extruder needs springs with a strong load force (25-35N). Problem was solved by switching to McMaster 9434K164 springs.
   

   About to disassemble the Makergear hotend after another jam (weak springs pictured)...

A Working Hotend – Weekend #7

J Head MKII Hotend for Wade's Extruder

The J Head MKII arrived in just two days! I wired up the resistor and thermistor, wrapped it all in Kapton tape, and fired up Repsnapper. Even without calibrating the extruder, it managed a test print.

Success! But still a long way from reliable printing…

J Head MKII after a few successful prints

Filament and Software Troubles – Weekends #8 and #9

Although the printer was technically working, there were still a few issues to work out.

ABS shavings on hobbed bolt. Tighten springs to resolve.

First, filament would randomly strip after anywhere from five minutes to three hours of printing. I’d have to pull the hobbed bolt out, clear the plastic shavings, and re-assemble. This issue took days to troubleshoot, but the solution was easy–tighten the extruder springs. Since then, no more stripped filament.

Next, ABS would barely stick to the acrylic bed. About halfway through the test cube print in the above video, the print ripped off the platform. Less than 1 in 5 print attempts would stick at all.

Verifying heatbed temp

In other words, a heatbed is an absolute must. Once more, Prusa’s MK1 PCB heatbed was sold out in North America; I resorted to ordering 25 from my PCB house.

Heatbed PCBs arrived in a week. I temporarily mounted one atop the acrylic bed using 1/4″ Nylon standoffs, following Prusa’s “final” mounting solution–glass covered with Kapton tape and attached with bulldog clips.

For wire, I used 14AWG THHN, rated for 105C. The outer PCB traces connecting to the power supply leads are thicker, so this region of the board is cooler and it’s safe to use 105C wire here. Glass came from Lowes for about $2. I had to trim the corners (tip: use scissors underwater).

Because Gen6 has no heated bed support, the heatbed is wired directly to my 12V, 15A power supply. The glass surface reaches 100C in about five minutes, and 110C after 15-30 minutes, as measured by thermal probe.

First print with Prusa MK1 heatbed + SFACT!

Up to this point, I’d used Repsnapper as a host, as per severely out of date documentation from Mendel-Parts.com. It was time to move to SFACT and Printrun/Pronterface. Printrun is a solid graphical interface, which relies upon SFACT/Skeinforge for gcode generation. It’s daunting at first, but prints beautifully. Just one downside: Skeinforge is CPU hungry. Kliment (author) says he’s working on optimization.

I was also using FiveD firmware downloaded from Mendel-Parts.com. FiveD lacks acceleration and I was seeing occasional pauses during Z-axis movement. I flashed to Kliment’s latest Sprinter firmware and increased the baud rate to 38400. No more hiccups. Also, acceleration is a glorious thing.

While editing Sprinter’s configuration.h file, I took the time to document proper equations for the Prusa:

• Formula for X steps per mm = Y steps per mm = (Steps)/(Microstepping *BeltPitch*PulleyTeeth)
• Formula for Z steps per mm = (Steps)/(Microstepping*Zd)
• Formula for E steps per mm = (Steps*ERatio)/(pi*Microstepping*BoltDiamter)

• Steps = Number of motor steps per one revolution (200 for 1.8 degree, 400 for 0.9 degree motor, etc.)
• Microstepping = Microstepping ratio of controller (1/8 for Gen6, 1/16 for Pololu, etc.)
• BeltPitch = Distance in millimeters between teeth of belt (5.00mm for T5, 5.08mm for XL, etc.)
• PulleyTeeth = Number of teeth on the motor pulley gear (default is 8 teeth for T5 gears; XL gears may use 10)
• Z_d = Distance in millimeters between threads of Z rods (1.25mm for M8)
• ERatio = Gear ratio for extruder gears (Wade’s Extruder: 39/11, Accessible Wade’s by Greg Frost: 43/10, Adrian’s Extruder: 59/11, etc.)
• BoltDiameter = Diameter of hobbed bolt in millimeters, measured at hobbed section

These formulas have since been added to the Prusa Wiki.

Minor Tweaks – Weekend #10

Replaced acrylic bed with MDF, added Z constraints, and installed helical Z couplings

Heat warps acrylic, so within days of installing the heatbed, I had to replace the acrylic printbed with 1/4″ MDF bed ($6 from Lowes and half an hour with a jigsaw). Acrylic was junk to begin with. It flexes too much, even without heat, which added great difficulty to bed alignment. Use MDF.

I also replaced the plastic Z-couplers with aluminum helical couplings and added ScribbleJ’s Prusa Z Rod Constraints.

My Prusa has been exiled from the kitchen. It now resides in the basement, where it’s printed for 90+ hours in the past two weeks, including two full sets of Prusa parts.

What comes next?

• Build a Prusa with 0.9° steppers and T2.5 belts
• Try PLA with a J-Head MKIII-B and Greg Frost’s Hinged Accessible Extruder
• Additional calibration…need to eliminate corner blobs

FINAL THOUGHTS

1. I should’ve started blogging 10 weeks ago.
2. If you build a Prusa, use LM8UU linear bearings, a heatbed, a good hotend (J Head MKIII-B!), and strong bed and extruder springs. Also grab the latest popular firmware and software. And buy a digital caliper.
3. RepRap is not cheap. If you build one, you will find the need to build more. That said, it would’ve been cheaper if I’d built a hybrid SAE + metric Prusa. See also this Wade’s Extruder BOM.
4. Don’t build a RepRap on the kitchen table. Does not please the wife.

Special thanks go to: Nick, Reifsnyderb, and everyone on Freenode #reprap!

Live USPS Tracking?

E-tailers and consumers know that USPS tracking is a joke. For several years, Delivery Confirmation (DC) was just what its name implies—a method of checking that a package had been delivered. Although USPS.com displays a “Track and Confirm” search field on their website, DC numbers have historically returned two points of information (acceptance and delivery), coupled with one very misleading statement:

Information, if available, is updated every evening. Please check again later.

• Your item was accepted at 1:06 PM on May 23, 2008 in St. Louis, MO 63103.

Information was generally not updated until the package had been delivered. More tracking points have begun to show up in the past 5 years, but we were still told to maybe expect more information each evening. Lies.

I happened to check on an incoming Priority shipment last week and noticed a new statement:

The item is currently in transit to the destination. Information, if available, is updated periodically throughout the day. Please check again later.

	Arrival at Post Office, January 06, 2011, 6:53 am, MARYVILLE, IL 62062
	Processed through Sort Facility, January 06, 2011, 12:45 am, HAZELWOOD, MO 63042
	Electronic Shipping Info Received, January 05, 2011
	Acceptance, January 04, 2011, 9:06 am, MERRIFIELD, VA 22081

Well, that’s new, but I wasn’t sure if I should believe it. So I checked again later:

	Out for Delivery, January 06, 2011, 8:10 am, MARYVILLE, IL 62062
	Sorting Complete, January 06, 2011, 8:00 am, MARYVILLE, IL 62062
	Arrival at Post Office, January 06, 2011, 6:53 am, MARYVILLE, IL 62062
	Processed through Sort Facility, January 06, 2011, 12:45 am, HAZELWOOD, MO 63042
	Electronic Shipping Info Received, January 05, 2011
	Acceptance, January 04, 2011, 9:06 am, MERRIFIELD, VA 22081

What’s this? Live tracking, from USPS?!

	Notice Left, January 06, 2011, 9:13 am, MARYVILLE, IL 62062
	Out for Delivery, January 06, 2011, 8:10 am, MARYVILLE, IL 62062
	Sorting Complete, January 06, 2011, 8:00 am, MARYVILLE, IL 62062
	Arrival at Post Office, January 06, 2011, 6:53 am, MARYVILLE, IL 62062
	Processed through Sort Facility, January 06, 2011, 12:45 am, HAZELWOOD, MO 63042
	Electronic Shipping Info Received, January 05, 2011
	Acceptance, January 04, 2011, 9:06 am, MERRIFIELD, VA 22081

USPS has again failed to announce any of these changes, so it’s hard to say what improvements we’re actually seeing (it could be limited to selected cities). I checked a few random customer shipments and each returned similar tracking information. The Click-n-Ship site also has a new layout, so it’s safe to say they’re rolling out new features:

Improved tracking is a great step forward for the struggling government agency, but this leaves me wondering why it hasn’t been announced.

Has anyone else noticed better USPS tracking?

As usual, NPR delivered several gloomy economic reports this week as the U.S. Unemployment Rate rose again to 9.8%. I listened to interviewees on both sides of the fence share their stories. Some Americans are earnestly seeking employment, yet remain unemployed. Others admit that 6+ months of unemployment checks are simply an incentive for them to sit at home until the free money stops coming.

Today my company received a letter from the State of Illinois’ Department of Employment Security. Inside was our Annual Contribution Rate Determination, aka, a declaration of how much Unemployment Tax/Insurance we must pay:

2011 Illinois Contribution Rate Determination: 3.8%!

This year’s rate has increased about 0.5% over last year’s, which is a direct result of continued high unemployment and Illinois’ nearly bankrupt status.

Words cannot express my frustration with this policy. The nature of the company necessitates that it conduct business as a corporation. We work only with freelancers and other small to mid-sized businesses and presently cannot afford additional employees. If the company were to dissolve, yours truly would have no route to claim unemployment. So why does Illinois demand a “Contribution Rate” of 3.8%? As Larry pointed out, unless we are aiming for socialism, a single-employee S-corporation should contribute 0%. Sure, this doesn’t help those who are unfortunately unemployed–but taking more money from a small businesses certainly doesn’t help this economy.

Right now, we need cash on hand for R&D and new product launches, which will in turn pay our freelance workers and partnering manufacturing companies, many of which are local! The more we invest, the better able we are to expand sales and generate growth. This logic didn’t set well with me until I found myself in charge of a small business. For situations like ours, higher taxes hurt.

The Workaround

Servers perform these frustrating redirects by reading the browser’s “user-agent” ID. So, if we spoof the iPhone browser’s user-agent ID, web servers will believe the iPhone is a regular desktop browser. But, the iPhone’s Safari browser doesn’t support user-agent spoofing. This leaves us with two choices:

1) Jailbreak the iPhone

or

2) Install a browser app that supports user-agent spoofing

I went with option (2) and downloaded a browser called JourneyLite.

1) Download the free JourneyLite app:

2) Launch JourneyLight and tap the “+” icon at the bottom

3) Select “Settings”

4) Change “Pretend to be” to “Firefox 3.0″, then hit Done

You’re now surfing like a ninja. No more mobile sites:

Car Audio: Without a Car

In an earlier decade, I accumulated an inane number of car audio subs and amplifiers. I’ve finally come to my senses (thank you, tinnitus :-/). But, I have yet to find a more pleasing sound than that which comes from an oldschool pair of Infinity Perfect 10.1‘s in a custom sealed box, powered by a JBL BP600.1. So, the pair now resides in my office, rather than my hatchback. This initially posed one problem:

How does one power a 12V amplifier indoors?

Obviously, we need a way to convert 120V_AC mains to 12V_DC at 600W+. High output DC power supplies are not cheap. It makes more sense to find a 4 ohm capable home audio subwoofer amp, but those are not cheap either.

There’s an easy solution, and that is to sacrifice an old ATX power supply (PSU). Audiophiles are now cringing; switching power supplies are a no-no in the audio realm. But so are Class D amplifiers, like the JBL BP600.1, which has an internally limited frequency response of just 10-320Hz. And again, it’s a car audio amplifier. This means its power supply stage was designed with excellent noise rejection, and thus, a switching power supply is a fine match.

Numerous tutorials explain How to Convert a Computer ATX Power Supply to a standalone DC supply, but most are targeted towards low power projects. In this instance, we need more than a few watts. We need every last electron the PSU can muster.

I pulled an old Thermaltake 430W PSU out of the closet. Before putting it to work, two modifications were needed:

1. Combine all 12V wires and all ground wires to create two heavier-gauge wires, for adequate ampacity
2. Force the power supply to turn on

430W ATX PSU Specifications

ATX PSU’s manufactured after ~2005 sometimes feature multiple +12V rails. While it should be safe to merge multiple 12V rails, doing so could be a bad idea for this project (possibly more noise from multiple switching supplies). Multiple rails are usually labeled on the side of the supply as “+12V1″ and “+12V2″, or similar. Luckily, the supply I butchered has only a single +12V rail rated for 18A, meaning 216W of 12V goodness. This isn’t enough power to push the 600W RMS amp to its limits, but that’s okay. I don’t need 600W of bass in my office.

Safety

Note that this project involves potentially lethal mains voltages (120V_AC). A PSU should never be opened or modified by an unqualified individual. Perform these modifications at your own risk! I am not responsible for any damages that may occur as a result of this article.

Capacitors in a PSU store a large amount of energy. With the PSU running, turn its switch off (or pull the power cord) and wait for the connected device(s) to shut off. Only open the PSU after you are sure it is drained of energy.

Wire Pruning

A modern ATX 2.x PSU contains a 24 pin motherboard header, at least one 4- or 6-pin +12V connector, and a multitude of +5/+12V molex, floppy, SATA, and GPU connectors. We only need the black wires (ground) and +12V wires (yellow). Ignoring the safety warning stickers, I removed the cover and proceeded to extract all extra wires. All useless wires from the ATX motherboard header and various connectors landed straight on the circuit board. These were easily removed with wire cutters.

A few inches of the green “power on” wire (ATX pin 20/24 as explained here) was preserved and soldered to a ground wire. I temporarily used hot glue, but this isn’t safe or recommended. Use twist wire caps or heat shrink wrap for a permanent installation.

Top view of PSU with cover removed and extra wires pulled

Some leftover ATX wires

Green ATX wire tied to ground

With the PSU cover back on, I untangled the remaining yellow & black wires, trimmed them to equal lengths, and wired the modified PSU to the amplifier. The final product, with tidy wire-ties in place:

Yellow to +12V and Remote, Black to GND

Results

The BP600.1 and ATX PSU deliver deep, clean, ridiculous house-shaking bass. The setup absolutely blows away my Boston Acoustics CSSUB10B (and especially the lowly Logitech Z-2300′s). I’ve only cranked the volume too high a few times in the past year. When the amp draws too much current, the PSU struggles to keeps up and the amp’s LEDs dim during bass hits. It’s rare that I need/want ~135dB bass in my office, though.

There’s one downside: Activating the subwoofer is slightly inconvenient since the PSU must be manually switched on. I’ve tried going back to my home audio subs, but they don’t stack up to the quality of the Infinity Perfects.

First, a bit of background info. There are three types of authentication that Verizon can use:

A) DHCP only — Verizon reads your current MAC address and assigns an IP address
B) PPPoE only — A username/password is required, but MAC address is ignored
C) Both PPPoe and DHCP

Like many other Verizon users, I initially setup MAC address cloning on our router, expecting to trick Verizon’s servers. I then setup PPPoE and thought we would be done. No go!

As noted on the Practically Networked forums, there is no need to clone the MAC address. In fact, don’t do that; it’s wasted effort and can wreak havoc between the cloned device and router. Unlike many cable companies, Verizon doesn’t care about your modem’s MAC address. The address is used only for the length of the IP address lease, which is just a few hours. If you tell the modem to release its assigned IP address, Verizon will instantly accept another modem/MAC address. Releasing the IP is easy to do from the modem configuration page, by the way.

Verizon provided us with a Westell 6100 DSL modem. Like many modern DSL modems, the Westell 6100 has an internal router which must be disabled (aka, “bridged”) for proper NAT routing. You can use a router behind a router, but this leads to numerous problems (impossibly blocked ports, broken VPNs, etc.). Anyway, Verizon has a seemingly simple tutorial describing how to bridge the Westell 6100, so that these problems can be avoided. Unfortunately, the tutorial isn’t entirely accurate…

Our most important discovery of the day: Verizon uses different authentication methods in different regions of the country. My sister lives in Tampa, FL; several folks on various message boards claimed that Verizon employs PPPoE + DHCP in this area. This led to our demise–although she has a username and password with Verizon for e-mail and billing, her Verizon DSL does not use PPPoE. Verizon’s own tutorial (above) even alludes that PPPoE is used. It was not for us.

Call Verizon tech support to find out which type of configuration your DSL line uses. It only took 5 minutes on the phone to obtain this critical piece of information. Granted, had I been in front of the PC myself, I probably would’ve gathered this info from the start by looking through the Westell’s configuration/status page.

No matter which authentication method your Verizon line uses, the Westell 6100 needs to be bridged. If using PPPoE only, enter your account credentials in your router (after releasing the connection and bridging the Westell 6100). If your DSL uses DHCP only, release the DSL and bridge the Westell 6100, but set your router to Automatic-DHCP instead of PPPoE. Routers are generally set by default for Automatic-DHCP negotiation.

Due to my sister’s technical ignorance, we ended up ditching the Westell 6100. Older DSL modems (ie, those without built-in routers) can be used as long as they use the same VPI/VCI settings. So, we connected an old SpeedStream 5360, previously used with AT&T DSL service. Her router immediately established a connection to Verizon with the old SpeedStream. These modems can be found for hardly $10 on eBay. Just make sure to disconnect/release the Westell 6100 first.

Google searches revealed nothing definite. Some folks claimed that upgrading to a DOCSIS 3.0 modem brought much greater performance, even on DOCSIS 2.0 lines. Some claimed no changes at all. I still wasn’t sure whether my area supported DOCSIS 3.0 or not, and further, I assumed that those who saw major benefits were subscribers of top-tier, 25Mb+ services. Then I read about Powerboost®, which is apparently the reason I see download speeds above 8Mb/sec. So, if I was right about my cable line, channel bonding might further improve performance.

Motorola’s SB6120, a DOCSIS 3.0 modem, was on sale at Best Buy last week. I had to pick one up to satisfy my nerdy curiosity.

The SB6120 makes things simple: Blue status LEDs = channel bonding (DOCSIS 3.0); Green LEDs = no channel bonding (not DOCSIS 3.0). Sure enough, the SB6120 booted up with a blue “Receive” LED. Logging into the status page (http://192.168.100.1) confirmed 4 bonded channels.

LEDs top to bottom: Link, Online, Send, Receive, Power

Charter automatically directed me to http://install.charter.com to verify the MAC address and account number. Within a few minutes, it was ready to go.

Benchmarks

All tests were made from a PC running Windows 7 Pro 64-bit, Firefox 3.6.2, with a gigabit LAN connection.

The real question was, had I wasted $85 to put another blue LED in my basement? Let’s see:

Benchmarked w/Motorola SB61020

Unfortunately, I discovered that bandwidth varied greatly depending on the test server (although always better than DOCSIS 2.0). This is something I hadn’t noticed before. Below is a SpeedTest.net log of test results with the Motorola SB6120. Benchmarks with asterisks (*) were taken while streaming a Netflix movie on another PC.

The table below is a log of results using the Linksys CM100 modem on DOCSIS 2.0. I hadn’t realized how poorly the St. Louis, MO server performs through Charter, despite it being nearby. Only a single benchmark was made an an alternative test server.

The chart below plots the average/min/max upload and download figures from the above tables.  Latencies were averaged only for St. Louis, MO test results since benchmarks were not made on identical servers for both modems. The SB6120 improved latency by 0.55ms (negligible).

Charter Express - SpeedTest.net Results (DOCSIS 2.0 vs 3.0)

On average, DOCSIS 3.0 boosted download speeds on the local St. Louis test server by 1.74Mb/second (+11%), with 0.55ms less latency (3% improvement). Taking other servers into consideration, the benefits of DOCSIS 3.0 are extremely obvious. Average download speed increased by 12.16Mb/second (+77%), and maximum throughput increased by 43.89Mb/second (+291%).

Summary

I must admit that I see no difference in browsing speed between DOCSIS 2.0 and DOCSIS 3.0. File downloads are obviously faster and make the modem upgrade well worth the cost.

If you’re in the market for a new cable modem, you might as well spend a bit more for the higher performance of a DOCSIS 3.0 modem. The performance gains are probably even greater for those subscribed to faster cable plans–I’ve barely put the SB6120 to work. With faster service, it’s capable of much more.

Since the WNR3500L had made no use of its gigabit switch during 802.11n transfers, I settled for a simple router, the Buffalo WHR-HP-G300N:

Buffalo WHR-HP-G300N, Fresh out of its retail box

Buffalo WHR-HP-G300N: Specifications & Features

On paper, the WHR-HP-G300N is nothing special. Featuring single-band, dual-antenna 2.4GHz output powered by a 400MHz Atheros AR7240 radio, paired with only 32MB RAM and 4MB flash, and a 100MB/sec switch, the WHR-HP-G300N is outdone by most other 802.11n routers on the market. The Asus RT-N16, for instance, offers a faster processor with 4x the RAM and 8x the flash capacity of the WHR-HP-G300N. Buffalo has also forgone extras, such as USB ports, which are found on more expensive routers.

However, the WHR-HP-G300N makes up for its limited feature-set with its low price tag and High Power output (hence, the “HP” portion of its model number). Not only has Buffalo given the WHR-HP-G300N two external, adjustable (and replaceable) antennae, but all HP models utilize internal RF amplifiers on the receiving and transmitted ends of the radio. Therefore, I expected nothing less than excellent signal quality from the WHR-HP-G300N.

The WHR-HP-G300N also supports DD-WRT. In fact, Buffalo offers their own “official” DD-WRT build, which is included on CD with the router.

First Impressions

Like most shiny electronics, the WHR-HP-G300N shipped with a layer of plastic film to protect its super glossy black finish. The router itself feels solid, however, the buttons, antennae, and base stand feel somewhat cheap—but at this price point, I can’t complain. The green/amber status LEDs are less clever than the WNR3500L’s multi-color LED’s, but are clearly labeled on the side of the router.

Buffalo WHR-HP-G300N Powered On

A switch on the backside jumped out at me, which read, “Router: ON, OFF, AUTO”. I hadn’t noticed this feature prior to purchase, but was pleasantly surprised to see it there since it meant less work for me (no need for DD-WRT to create an access point).

Buffalo WHR-HP-G300N Rear Side

Router On/Off/Auto Switch

I initially changed the switch from its default “Auto” position to “Off”, since I would be using the WHR-HP-G300N purely as an 802.11n access point. But, I quickly discovered that this setting makes it impossible to access the router’s configuration page. The router is still able to act as an AP in “Auto” mode, but in this mode, it also fetches an IP address for itself from the primary router/DHCP server on the network, thus, making its configuration page accessible.

Stock Firmware

Buffalo’s factory firmware is surprisingly feature-filled (even packing a VPN server!) considering the router’s low cost. Maybe it’s due to years of familiarity, but I still find DD-WRT easier to navigate and configure. Buffalo’s firmware omits the advanced monitoring features found in DD-WRT, such as client SNR readings, bandwidth usage, wireless connection rates, etc.

Buffalo WHR-HP-G300N Stock Firmware

Throughput Benchmarks

The test setup is identical to that of the WNR3500L benchmarks made earlier this month, except with the obvious addition of the Buffalo WHR-HP-G300N configured as an AP on the main floor of my house. The network looks something like this:

Network Diagram of Test Setup

The WHR-HP-G300N’s stock firmware was set to Channel 1 during 20Mhz tests and Channels 1 + 5 during 40Mhz tests. Before taking any measurements, I observed the WHR-HP-G300N’s general wireless transfer stability on my netbook (the 65Mbps Link Speed is due to the default 20MHz configuration).

Two Large File Transfers to an Asus Eee PC via WHR-HP-G300N

As shown above, the WHR-HP-G300N’s stock firmware produces very stable results, free of link rate renegotiation or fluctuating transfer rates as experienced with the Netgear WNR3500L + DD-WRT. Consistent transfer rates translate to quicker overall transfers, which is exactly what the benchmarks reveal:

Transfer Rates of Buffalo WHR-HP-G300N (stock firmware) and Netgear WNR3500L (DD-WRT)

File transfer times to our MacBook Pro improved by roughly 10% with the WHR-HP-G300N, and by over 30% to our Asus Netbook (nearly 1 minute saved for a 580MB file!).  Below are the same measurements converted to average transfer rates.

Buffalo WHR-HP-G300N Transfer Rates with MacBook Pro

Buffalo WHR-HP-G300N Transfer Rates with Asus Netbook

The MacBook Pro’s dual-antenna 802.11n radio achieves a transfer rate increase of approximately +30% at 20Mhz and +36% at 40Mhz over the Netgear WNR3500L, while the Asus Eee PC’s musters a +12% boost at 20Mhz and +7% at 40Mhz.

Last, I stacked up the Buffalo WHR-HP-G300N against the old Linksys WRT54G v2.0:

Wireless Router Transfer Rates Compared

Average figures for all routers were calculated from benchmarks results from both laptops. This isn’t a very accurate picture since the Eee PC employs a fairly slow 802.11n radio. Peak figures are the maximum rates observed during benchmarking. The graph fails to convey that the Buffalo WHR-HP-G300N frequently operates at or near the recorded peak transfer rate, whereas the Netgear WNR3500L generally fluctuates near its average rate.

Summary

The above test results are real-world findings made on my home network. Clearly, the benchmarks are an unfair comparison since the WNR3500L was benchmarked on DD-WRT firmware and the WHR-HP-G300N was tested on stock firmware. Ignoring this injustice, the WHR-HP-G300N has increased my wirelsss-N throughput by roughly 30% in most cases.

Buffalo’s stock firmware prevents me from reporting SNR’s, but wireless coverage also seems to have improved.

And once again, the maximum 802.11n transfer rate observed of 6.09MBps (48.7Mb/sec) remains significantly below the WHR-HP-G300N’s 100Mb/sec switch speed.